In the related art, in a diesel engine, particulates contained in the exhaust gas are removed by arranging a particulate filter in the engine exhaust passage, using the particulate filter to trap the particulates in the exhaust gas, and igniting and burning the particulates trapped on the particulate filter to renew the particulate filter.
The particulates trapped on the particulate filter, however, do not ignite unless the temperature becomes higher than about 600° C., but, opposed to this, the temperature of the exhaust gas of a diesel engine is normally considerably lower than 600° C. Therefore, it is difficult to use the heat of the exhaust gas to cause the particulates trapped on the particulate filter to ignite and burn. Therefore, the particulates deposit on the particulate filter, and thus, the amount of the particulates removable by the particulate filter per unit time becomes small.
In an exhaust gas purification device comprising a particulate filter, the object of the invention is to keep an ability to remove the particulates, by the particulate filter, per unit time high.